1. Field of the Invention
The present invention relates to an electronic member having an illuminating device used in an operation portion of various electronic equipment and a rotary electronic component constituting the same.
2. Background Art
Recently, various electronic equipment such as an audio-visual equipment has been smaller in size and shorter in height. Furthermore, a mounting form in which an operation knob is illuminated from the inside has been increased and its illumination state has been demanded to be brighter and more visible. A conventional electronic member with an illuminating device used in such electronic equipment and a rotary electronic component constituting the electronic member are described taken a rotary encoder as an example.
FIG. 5 is a cross-sectional view showing a configuration of a conventional electronic member including a rotary electronic component. In FIG. 5, firstly, a configuration of a conventional electronic member including rotary encoder 10 that is a rotary electronic component is described. In FIG. 5, case 1 is made of an insulating resin and has a substantially annular outer shape. A portion forming a substantially annular-shaped inner peripheral wall makes cylindrical portion 1A. The inside of cylindrical portion 1A is hollow hole 2. Substantially annular-shaped case 1 is open upwardly and stationary contact 3 is disposed in a predetermined pattern on the bottom surface of the open portion. Terminal 4 that is conducting to stationary contact 3 extends to the outside of case 1.
Operation shaft 5 is made of an insulating resin that has a penetrating central portion. Sliding contact 6 is attached to the lower surface of flange portion 5B provided at the lower part of substantially cylindrical-shaped operation portion 5A. Operation shaft 5 is disposed on case 1 in a way in which the inner surface of substantially cylindrical-shaped operation portion 5A is rotatably combined with the outer surface of the cylindrical portion 1A. Cover 7 is attached to case 1 in a way in which it closes the open portion of case 1 and cover 7 is made of a metal plate. Cylindrical portion 1A and operation portion 5A combined with the outer peripheral side of cylindrical portion 1A protrude upwardly from a hole at the center of cover 7. Rotary encoder 10 as a conventional rotary electronic component is configured as mentioned above.
Rotary encoder 10 is mounted on wiring board 11 of electronic equipment (not shown) via terminal 4 by soldering. Furthermore, operation knob 12 is installed on operation portion 5A. The upper part of operation knob 12 protrudes from hole 13A of panel 13 of electronic equipment. Inside hollow hole 2 of rotary encoder 10, push-on switch 14 for producing an ON signal by pressing operation and LED 15 as an illuminating device are disposed. Wire leads 14A and 15A of push-on switch 14 and LED 15 are also attached to wiring board 11 by soldering, respectively.
Operation knob 12 has a double configuration composed of outer peripheral portion 12A at the outer side and middle portion 12B at the inner side. Outer peripheral portion 12A is attached to operation portion 5A of operation shaft 5 and operation shaft 5 can be rotated by the rotation of outer peripheral portion 12A.
On the other hand, middle portion 12B configured so that it is not rotated in accordance with the rotation of outer peripheral portion 12A is combined with cylindrical portion 1A movably up and down. In a position of middle portion 12B corresponding to a position above LED 15, light guide portion 12C formed of a light-transmitting translucent material such as acrylic resin is fitted. Furthermore, similarly, in a position corresponding to push-on switch 14, pressing portion 12D suspending downwardly is provided. The lower end of pressing portion 12D is brought into contact with the upper surface of driving portion 14B of push-on switch 14.
In this configuration, when outer peripheral portion 12A of operation knob 12 is rotated, operation shaft 5 of rotary encoder 10 is rotated, thereby allowing sliding contact 6 installed on the lower surface of flange portion 5B to rotate and slide on stationary contact 3. Sliding contact 6 and stationary contact 3 are electrically brought into contact with each other and broken so as to produce encoder signals. Furthermore, when middle portion 12B of operation knob 12 is pressed, pressing portion 12D depresses driving portion 14B of push-on switch 14 to allow a switch to operate. Thus, an ON signal is produced and LED 15 emits light. This light illuminates a portion of light guide portion 12C of operation knob 12 located in a position above hollow hole 2.
In middle portion 12B in a usual state in which a pressing operation is not carried out, pressing portion 12D receives an urging force upwardly from driving portion 14B of push-on switch 14. When the pressing operation is stopped, push-on switch 14 becomes in an OFF state, LED 15 is turned off, and middle portion 12B returns to the original position. The above-mentioned conventional configuration of an electronic member including a rotary electronic component is disclosed in, for example, Japanese Patent Unexamined Publication No. 2001-229779.
However, in such a rotary encoder having an illuminating device, which is a conventional electronic member including a rotary electronic component, since light guide portion 12C of operation knob 12 is disposed above hollow hole 2 formed by cylindrical portion 1A and located in a position apart from LED 15, it is necessary to use high intensity type LED 15 in order to obtain a brighter illumination state of light guide portion 12. Thus, the cost tends to be increased. Furthermore, light reflect diffusely in space between LED 15 attached to wiring board 11 and the operation knob to thus reduce the amount of light reaching light guide portion 12C of operation knob 12, which may lead to reduction of illumination intensity.